Safety relief valve for hot water heating systems



Sept. 19, 1933. R. w. JOHNSON 1,927,036

SAFETY RELIEF VALVE FOR HOT WATER HEATING' SYSTEMS 2 sheets-shewu Filed Jan. 10, 1930 Sept. 19, 1933. R. w. `joHNsoN 1,927,036

SAFETY RELIEF VALVE FOR HOT WATER HEATING' SYSTEMS Filed Jan. 10, 1930 2 Sheets-Sheet 2 HIM I Patented Sept. 19, 1933 SAFETY RELIEF VALVE FOR HOT WATER HEATING SYSTEMS Roy W. Johnson, Elkhart, Ind., assignor, by mesne assignments, to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application January 10, 193.0. Serial No. 419,794

3 Claims. (Cl. 1375-139) This invention relates in general to hot water Another important object of the invention heating systems, and more particularly toanovel resides in the provision of a vnovel form of organization of a safety relief valve with such thermostatically controlled valve, which is also 5 a system. l responsive to excessive pressures, and which is 55 Heretofore, various types of safety relief valves o'f simple and durable construction, reliable and have been proposed for use with hot water heateffective of operation, and easily and compara# ing systems. These valves have always been tively inexpensive to manufacture. incorporated in the pipe line which conducts Other objects and changes reside inv certainy the hot water from the heater into the stornovel features of the construction, arrangement age tank of the system, the'safety relief valve and combination of parts, which will be here- 60 being interposed between the hot water pipe inafter more fully described,.and particularly and an off-take pipe or drain connection. pointed out in the appending claims, reference Under normal conditions, thevalve is held closed being had to the accompanying drawings, form- 15 by a spring, but should the pressure in the ing a part of the speciicationa'and in which tank increase to a dangerous degree, the valve Figure 1 is a diagrammatic view in elevation,- is automatically opened, and the hot water flows showing a hot water system having a safety out through the off-take pipe, until the presrelief valve organized therewith in accordance sure is reduced to a safe point. It is also with the present invention; common to organize'with such a relief valve, Figure 2 is a detailed view partly in diameta thermostat subject to the temperature in the rical vertical section, and partly in elevation and hot water pipe, the thermostatlacting upon a illustrating the preferred form of safety relief rise in temperature, above a predetermined valve, embodying the present invention; maximum, to automatically open the relief valve Figure 3 is a similar view, showing another 25 and permit escape of the excess of the heated ferm Of the relief Valve; y r water. One of the disadvantages of these known Figure 4 iS a fragmentary detailed View in 7" types of relief valves has resided in the fact elevation, showing the adjustable dial Plate fOr that the'water in the hot water pipe between regulating the temperature at Which the therthe heater and the storage tank frequently bemostat functions to open the valve of Figure 3; 3 comes excessively heated before the water in Figure 5 iS e detailed perspective View 0f the the storage tank has'been heated to a `dan' lever employed between the thermostat'and thef gerous or excessive degree. This results in un valve of Figure 3; k 1 necessary operation of the relief valve, and the Figure 6 iS a Similar View 0f the adjustable draining of hot water from the storage tank collar interposed between the dial plate and the before any real occasion therefor has arisen. lever. 4

One of the principal objects of the present Referring to the drawings, and more particuinvention is to overcome `this disadvantage of larly to Figure 1, numeral 1 designates a storage the old systems, and to this end the present vtank yfor the hot water heating system, the tank invention proposes to incorporate the relief valve being of any appropriate construction, and havin the cold water supply pipe, adjacent to the ing the usualdrain connection 2. Aconventional storage tank. As a consequence of this organiheater 3 is provided, and may have an ordinary 90 zation of the relief valve in the cold water gas burner4 for heating a coil 5 enclosed within supply pipe, the valve `will not be opened until the usual casing 6. Coil 5 has its lower end excessively heated water has backed. up into the connected as at 7 to an intermediate portion of cold water supply pipe. This insures a full the storage tank, and has its upper end consupply of heated water in the storage tank benected as at 8 to the upper IJOI'lOIl 0f the Storage 95 fore any of the water is drained off, and has tank. been found to give an entirely satisfactory de- A cold water supply pipe 10 is provided, and gree of protection against excessive heating or as shown has a section 10', extending through dangerous pressures without unnecessarily wastthe top portion of the tank, Aand terminating 100 l ing'the heated water. l within the tank, and adjacent to the lower end waste pipe` or olf-take pipe 12 is prowhich the'waste pipe 12 connects. Intermediatethe coupling` 21 and nipple 22, the casing 20 is formed with an internal partition 23, into which a valve, seat 24 is threaded. A valve 25 coacts with valve seat 24, and has a stem 26, passing therethrough, and threaded into a valve carrier 27. The valve carrier 27 has depending guiding Ways 28, which slidably embrace the seat 24, to constrain the valve to proper movement.

' For biasing the valve 25 to closed position, .a compression coil spring 29 is provided, one end of the spring 29 abutting the carrier 27, and the other end thereof engaging an adjustable abutment 30 threaded into the casing 20. The tension of the spring 29 may be regulated by adjusting the abutment '30 to vary the pressure at' which the valve automatically opens. A cap 31 is threaded onto the casing 20 and encloses the abutment 30.

The present invention also proposes to automatically open the valve 25 in the event the water in the storage tank becomes excessively heated, and the excessively heated water backs up into the cold water supply pipe. For this purpose, a thermostat designated generally at 35 is provided, and has a bellows 36, the upper end of which is provided with a head 37. At the center of the head 37, a recess 37 is formed, to receive the rounded lower end of the valve stem 26. The bellows 36 also has aA lower head 38, which is xed in the hub of a spider 39, the arms of which are rigidly connected to the coupling 21. Ihe lower head 38 of the bellows is coupled to the upper end of a series of connected and hermetically sealed tubes 40 of copper or other material having the property of rapidly conducting heat. The tubes 40 and the interior of the4 bellows 36 are lled with ether orother volatile substance, which expands and contracts appreciably in response to temperature changes. As shown in the drawings, the tubes 40 project down into the cold Water supply pipe, and thus are inuenced by the temperature of the water therein. Normally, the substance within the bellows and tubes 40 is suiiiciently contracted to permit the valve 25 to remain seated under the iniiuence of the spring 29 an`d against the pressure in the system. However, if the water in the storage tank becomes excessively heated, and the excessively heated water backs up into the cold Water f supply pipe l0, the heated water acts on the tubes 40, and heats up the volatile substance within the tubes 40 and bellows 36. As a consequence, the bellows 36 is expanded, and as its lower head is fixed, its upper head moves upwardly, thereby moving the Valve stem 26 upwardly, and shifting the valve 25 away from its seat as shown in Figure 2.1'This permits the heated water to flow past the valve 25, 'and out through the waste 'pipe l2.

A modified form of safety relief valve is shown in Figures 3 to 6, and has a casing 45, provided with a nipple 46, which is coupled to the waste pipe l2, and also provided with a nipple 47, adapted to'be connected by a pipe 48 with the coupling 11 of the cold water supply pipe shown in Figure 1. An internal ported partition 49 is provided vwithin the casing between the nipples 46 and 47. A valve 50 is normally held engaged with the valve seat provided around part of the partition 49 under the influence of its compression coil spring 51, tensioned by an adjustable abutment 52. The abutment 52 is enclosed in a cap 53.

Withthe arrangement vas thus far described, the valve will automatically open, if excessive pressures accumulate in the storage tank and back up into the cold water supply pipe.

In order that the valve 50 may also autostorage tank becomes excessively heated, and the excessively heated water backs up into the cold water supply pipe, a thermostat designated generally at 55 is provided, and consists of a tube 56 of metal havingv a high coefciency of expansion. One end of the tube is threaded into a spider 57 formed yintegrally with orf. otherwise suitably connected to the nipple 47, and the opposite end of the tube 56 has a plug 58 threaded thereunto, and connected to one end of a rod 59, consisting of metal having a relatively low coefficient of expansion. The end of the rod remote from the plug 58 has a dial plate 60, thread- .matically open in the event that water in the edthereon, so that as the dial plate is turned it moves to some extent back and forth along the rod 59. The dial plate abuts a collar 61, freely slidable along the rod 59 and having diametrically 'opposite pointed projections 62, engageable in correspondingly formed recesses 63, provided in an aperture end 64 of a lever 65, fulcrumed at 66 on the casing, and having a rounded end 67, engaging a boss on the valve 50. By turning the dial plate 60, the collar 61 is shifted along the rod 59, thereby adjusting the lever 65 on its fulcrum, and varying the temperature at which the thermostat will act through the lever to open the valve. Accurate adjustment of the dial plate 60 is facilitated by yvirtue of provision 'on the plate of scalel markings 69, with which an larrow or pointer 70 on the casing coacts.

The invention claimed is:

1. A safety relief valve, .including a casing adapted to be connected to a lhot water heating system and to a waste pipe, a ported partition intermediate said connections, a spring bia'sed valve cooperable with said ported partition, a thermostat, including a tube and having a high coeilcient of expansion, and subject to the temperature'of water in the heating system, a rod connected to the tube, a dial plate adjustable on the rod, a collar slidable along the rod, under the control of the dial plate, and having diametrically opposite pointed projections, and a lever fulcrumed in the casing, having one end bearing against the valve, and having its other end engaged by the pointed projections of the collar.

2. In a device of the character described, a casing adapted to be connected to a hot water heating system and to a waste pipe, a relief valve regulating communication of the casing with the waste pipe, means for biasing the relief valve to closed position and providing for automatic opening of the relief valve in the event that the pressure acting on the valve exceeds a predetermined amount, a leverfulcrumed in the casing and bearing at one end against the valve. a

spring biased valve cooper-able with said ported partition, a thermostat including a tube having a high co-eilicient of expansion, a rod connected to the tube, a dial plate adjustable on the rod, a collar vslidable along the rod and having dia.- metrically opposite pointed projections and a lever Iulcrumed in the casing having one end bearing against the vvalve and having its other end engaged by the pointed projections o1' the collar.

ROY W. JOHNSON. 

